no longer waterproof, what do I do?

First, spot clean the bag to the best of your ability. When you add any water-proofing, it will seal in those stains and spots. There are forms of re-water proofing chemicals. If you wish, you can use Tech Wash and follow up with their ReviveX product. That's a pretty thorough method. Otherwise, spot clean and apply Scotchguard --it will keep dirt and misty rain off your bag.

I have used "Stormproof" by Stormsure.

This is a durable water repellent and I used for reproofing my outdoor rain coats. It is water based and you simply spray it on and then dry it in a warm environment. The rain just rolls off the surface after treatment. I have now used it on many hats, coats, leather shoes and even my outdoor garden furniture (it stops algae and moss from growing on the wood!) It seems to work on every fabric and surface.

Here is the link to their web page...https://www.stormsure.com/index.php/cata...